Jump Tracer 
-------------

Well, I don't feel like writing complete dox right now - I'll do it
after I add some missing features, such as making .CRK files,
to Jump Tracer.

I'll just try to explain the Jump Tracer's cracking method now.
The main idea is to compare two or more different ways of program's
execution and find where it branches. After that we can change or
remove the condition so that the program will always run the desired
way.

For example, this can be used to remove copy protection (this version
of Jump Tracer uses only some simple methods to fool anti-debugging
code, so it may not always work properly). To do it you need to trace
the program to crack at least twice - the first time with the
required keydisk, plug in LPT port, entering the correct password,
etc.; and the second time without the key.

Also, you can crack games (Jump Tracer is especially useful when
cracking things like making it possible to move through walls, that
couldn't be done with Player's Tool or Game Wizard), remove shareware
delays (it's done by enabling saving of jumps being executed for
different periods of time - the first time while in delay loop and
the second slightly before the loop ends) and finally you can simply
change program's behavior (for example disable some annoying functions).

 Usage Example
---------------

Let's suppose we need to disable the F1 key in Volcov Commander. ;)
BTW, I'm still using its beta version because the 4.0 release does
not support searching for hex bytes using Alt-F7. ;(

Run Jump Tracer:

jmptrace c:\vc\vc.com

----------------------------------------------------------------------
Jump Tracer Version 1.2  Copyright (c) 1995-96 by Solar Designer \ BPC

Use <Caps Lock> to turn saving on/off while tracing, left <Shift> to
abort Trace, Quit? T

Enter program parameters:

The Volkov Commander, Version 4.00.040 beta
Copyright (C) 1991-1994 by VVV, Kiev.

[Press <Caps Lock>, <F1>, <Esc>, <F10>, <Enter>, <Caps Lock>]

Please, identify this state as:
1st, 2nd, Nothing? 1

You've saved 1 dump by now; at least 2 different dumps are required
to crack

Trace, Quit? T

Enter program parameters:

The Volkov Commander, Version 4.00.040 beta
Copyright (C) 1991-1994 by VVV, Kiev.

[Press <Caps Lock>, <F10>, <Enter>, <Caps Lock>]

Please, identify this state as:
1st, 2nd, Nothing? 2

You've saved 2 dumps by now; you can compare them

Trace, Compare, Quit? C

Smartly comparing and filtering...

?: Internal offset 364D: ? N

[Some other lines may appear here if, for example, more than a second
passed while tracing and clock in VC redrawn. If so, make more than 2
dumps to find the exact offset]

Return, Display? D

The program will now be traced once more, you may have to enable
saving for a long time to find the desired jump

Enter offset: 364D
Enter program parameters:

The Volkov Commander, Version 4.00.040 beta
Copyright (C) 1991-1994 by VVV, Kiev.

[Press <Caps Lock>, <F10>, <Enter>, <Caps Lock>]

PSP+0299:AFA6: 75 06 E8 CB C7 58 EB F1 44 44 C3 55 8B EC 83 EC
Use 1st state: PATCH NOT AVAILABLE
Use 2nd state: EB

Please, identify this state as:
1st, 2nd, Nothing? N

Return, Display? R

You've saved 2 dumps by now; you can compare them

Trace, Compare, Quit? Q
----------------------------------------------------------------------

Here we got a pattern to search for in VC.COM - do it using VC itself
and change the first pattern's byte value to EB. If you patch the
first two bytes with 90 90 instead, you won't be able to exit help. ;)
However, this state is unstable - that's why Jump Tracer said that
such patch is not available. The same about question mark in the
comparison result.